Locating devices, systems, and methods using frequency suites for utility detection

ABSTRACT

This disclosure is directed to utility locating systems, devices, and methods using frequency suites of simultaneously processed signals emitted from buried utilities to locate the buried utilities or other hidden or buried conductors.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority under 35 U.S.C. § 119(e) to U.S.Provisional Patent Application Ser. No. 62/209,824, entitled COMBINEDPASSIVE AND ACTIVE UTILITY LOCATING DEVICES, SYSTEMS, AND METHODS, filedAug. 25, 2015, the content of which is incorporated by reference hereinin its entirety.

FIELD

This disclosure relates generally to utility locating devices, systems,and methods for locating buried or otherwise hidden utilities or otherconductors by sensing magnetic field signals emitted from the utilitiesor other conductors. More specifically, but not exclusively, it relatesto devices, systems, and methods for locating buried utilities bysensing magnetic field signals emitted from both passive and activelycoupled current signal sources.

BACKGROUND

Incidents caused by inaccurately located utility lines have resulted incostly damage to infrastructure as well as loss of human life. In atraditional utility line locating operation (also denoted herein as a“locate” for brevity), a user moves about a locate area with a hand-heldutility locator device (also denoted herein as a “utility locator” orsimply “locator” for brevity) to detect magnetic field signals emanatingfrom utility lines and/or other conductors hidden or buried underground.Existing locators are typically configured to detect either signalsresulting from current signals intentionally coupled to the utility line(denoted herein as “active signals”), such as with a transmitter device,or “passive signals,” which are signals resulting from currentsincidentally induced upon the utility from overhead utility lines, radiosources (e.g., from broadcast antennas or other signal sources), orother electromagnetic signal sources. Traditional locating uses one orthe other type, but typical not both simultaneously.

Accordingly, there is a need in the art to address the above-describedas well as other problems.

SUMMARY

In exemplary embodiments, combined passive and active signal locatingdevices, systems, and methods of the present disclosure may include autility locator for receiving and processing electromagnetic signals atmultiple frequencies simultaneously and generating locating output databased on the processed plurality of signals. These may include one ormore active and one or more passive signal suites or one or more suitesof both active and passive signal frequencies. The signals may includeone or more active signals coupled to the utility using one or moreutility transmitters and/or one or more passive signals resulting fromcurrents induced or coupled from signal sources within the locateenvironment such as power lines, radio broadcast stations, or othersources.

This disclosure relates to devices, systems, and methods for locatingburied utilities using both active magnetic field signals, those signalscoupled to the utility using one or more utility transmitters, andpassive magnetic field signals, those signals which may incidentally beinduced from signal sources within the locate environment, emitted fromthe utilities or other buried assets. The combined passive and activesignal locating devices, systems, and methods of the present disclosuremay include a utility locator for receiving and processingelectromagnetic signals at multiple frequencies which may includefundamental frequencies and harmonic frequencies simultaneously andindependently. The signals may be collected with a suite of two or moresignals, typically harmonics or related by integer factors. Such signalsuites may include odd harmonics or even harmonics or both.

The systems, devices, and methods herein may use comparison of solutionsat different geographical locations within the locate operation to allowfor a refined determination of location, depth, and/or type ofutility/utilities and/or other conductors. In some embodiments, thecomparison may be or include principal component analysis (PCA)independent component analysis (ICA), and/or other component analysis orcorrelation methods.

For example, in one aspect the disclosure relates to a buried utilitylocator. The locator may include, for example, an antenna array forreceiving magnetic field signals from a buried utility in two or moreorthogonal directions, the antenna array having a bandwidth including aplurality of predefined signal frequencies in a predefined firstfrequency suite, a receiver operatively coupled to the antenna array forgenerating a receiver output signal including amplitude and/or phaseinformation of first two or more signal components in two or moresimultaneously received signals of the first frequency suite, aprocessing element operatively coupled to the receiver for receiving thereceiver output signal and generating a first set of data associatedwith the two or more signal components of the first frequency suite, anon-transitory memory for storing the first set of data, and a displayto render a visual output corresponding to the determined first set ofdata.

In another aspect, the disclosure relates to a method for locatingburied utilities. The method may include, for example, receiving, at anantenna array for receiving magnetic field signals from a buried utilityin two or more orthogonal directions, a plurality of magnetic fieldsignals at predefined signal frequencies in a predefined first frequencysuite, generating, in a receiver coupled to an output of the antennaarray, a receiver output signal including amplitude and/or phaseinformation of first two or more signal components in two or moresimultaneously received signals of the first frequency suite,generating, in a processing element coupled to the receiver, a first setof data associated with the two or more signal components of the firstfrequency suite, storing, a non-transitory memory of the locator, thefirst set of data, and rendering, on a display of the locator, a visualoutput corresponding to the determined first set of data.

The combined passive and active locating devices, systems, and methodsherein may be used in mapping utility lines and/or other like assets.

In another aspect, the disclosure relates to means for implementing theabove devices and methods.

In another aspect, the disclosure relates to a non-transitory computermedium including instructions for use by a processing element toimplement the above-described methods, in whole or in part.

BRIEF DESCRIPTION OF THE DRAWINGS

The present application may be more fully appreciated in connection withthe following detailed description taken in conjunction with theaccompanying drawings, wherein:

FIG. 1A an illustration of details of an example utility locatingoperation.

FIG. 1B illustrates details of an embodiment of a method to phase lock autility locator to the power grid.

FIG. 1C illustrates example embodiments of active and passive frequencysuites.

FIG. 2 illustrates details of an embodiment of a method for combinedpassive and active locating method.

FIG. 3 illustrates details of an embodiment of a graphical userinterface for a utility locator device.

FIG. 4 illustrates details of an embodiment of a graphical interfaceshowing locate information determined based on a first frequency suite.

FIG. 5 illustrates details of an embodiment of a graphical interfaceshowing locate information determined based on a second frequency suite.

FIG. 6 illustrates details of an embodiment of a graphical interfaceshowing display of locate information.

FIG. 7 illustrates details of an embodiment of a graphical interfaceshowing locate information of a utility with a single line.

FIG. 8 illustrates an example graph showing one spectral signature ofmeasured frequencies of a frequency suite or suites.

FIG. 9 illustrates an example graph showing another spectral signatureof measured frequencies of a frequency suite or suites.

FIG. 10 illustrates details of an example spectral signature of measuredfrequencies from an active signal.

FIG. 11 illustrates details of an embodiment of a method for determiningutility information based on a spectral signature.

FIG. 12 illustrates details of another embodiment of a method fordetermining utility information based on a spectral signature.

FIG. 13 illustrates details of another embodiment of a method fordetermining utility information based on a spectral signature.

FIG. 14 illustrates details of an embodiment of a method for windowingcorrelating sets of signal measurements.

FIG. 15 illustrates details of an embodiment of a method for refiningmovement data based on changes in electromagnetic signal.

FIG. 16 illustrates details of an embodiment of a method for adjustingfilter bandwidth and/or averaging of filter output signals based onutility locator movement and/or other adjustment/averaging criteria.

FIG. 17 illustrates details of an embodiment of a method for determiningtargets of opportunity from a spectral scan.

FIG. 18 illustrates details of an embodiment of a graphical interfacedisplaying targets of opportunity as acquired from a prior spectralscan.

FIG. 19 is an illustration of an example locate operation demonstratingtargets of opportunity along a spectral scan path.

FIG. 20 is another illustration of an example locate operationdemonstrating targets of opportunity along a spectral scan path.

FIG. 21A is an illustration of an example target of opportunity along aspectral scan path with distinct edges.

FIG. 21B is an illustration of an example target of opportunity along aspectral scan path wherein the measured spectral signature graduallytransition.

DETAILED DESCRIPTION OF EMBODIMENTS Overview

In exemplary embodiments, combined passive and active signal locatingdevices, systems, and methods of the present disclosure may include autility locator for receiving and processing electromagnetic signals atmultiple frequencies simultaneously and generating locating output databased on the processed plurality of signals. These may include one ormore active and one or more passive signal suites or one or more suitesof both active and passive signal frequencies. The signals may includeone or more active signals coupled to the utility using one or moreutility transmitters and/or one or more passive signals resulting fromcurrents induced or coupled from signal sources within the locateenvironment such as power lines, radio broadcast stations, or othersources.

As used herein, an “active signal(s)” refers to a magnetic field signal(magnetic component of an electromagnetic field created by a flowingcurrent) resulting from a current intentionally impressed upon a hiddenor buried utility line (e.g. a pipe, conduit, cable, etc.) or otherconductive object (e.g., a non-conductive utility such as a plastic pipemay have an associated tracer wire or other conductor buried with it tofacilitate locating it) that is being located with a utility locator.Such an active signal is typically generated with a utility transmitterdevice or induction device, such as an induction stick or clamp, or withanother transmitting element with a direct or inductive coupler thatintentionally induces, directly couples, or otherwise impresses acurrent signal at one or more predetermined frequencies onto one or moreutility lines and/or other conductors. Locating operations that uselocators to sense active signals for locating pipes or other conductorsmay be referred to as “active locating” for brevity.

The term “passive signal(s)” refers to those signals not purposefullyimpressed onto utility lines and/or other conductive objects but ratherinduced or otherwise coupled through sources in the environment such asradio signals, power line transmission cables (and their associatedelectromagnetic signals), and the like. Such passive signals may, forexample, may result from electromagnetic field coupling with overheadpower lines, radio station signals, cellular or other terrestrialwireless signals, other radio signals, and/or other signal generatingelements that produce signals that couple onto utility lines and/orother conductive objects within the locate area. Passive signals mayalso include electromagnetic fields generated by currents intentionallyimpressed onto hidden or buried conductors, such as from buried AC powerlines or other current signal sources that are not applied to theconductors as part of a locate operation using a transmitter or othercurrent coupling device. Locating operations that use locators to sensepassive signals for locating pipes or other conductors may be referredto as “active locating” for brevity.

The term “spectral scan” as used herein refers to an array signalmeasurements taken at various individual frequencies of a frequencysuite simultaneously. The resulting array values may be represented asamplitudes, amplitudes and phases, vector data, or other signalrepresentations. The spectral scan may be done by processing a widebandsignal having a bandwidth that extends over two or more frequencies(preferably all frequencies) of a frequency suite to extract informationabout separate signal components. For example, the wideband signal maybe processed, such as by using a discrete Fourier transform (DFT) (orother signal processing techniques, such as parallel narrowband signalprocessing, other transform methods, and the like) to simultaneouslyextract discrete frequency signals from the component signals of thefrequency suites.

The term “buried objects” and “buried utilities” as used herein includesobjects located inside walls, between floors in multi-story buildings orcast into concrete slabs, for example, as well as objects below thesurface of the ground, such as pipes or other conductors buried belowthe ground surface or under roadways, etc. In a typical application aburied object or buried utility is a pipe, cable, conduit, wire, orother object buried under the ground surface, at a depth of from a fewcentimeters to meters or more, that a user, such as a utility company,construction company, homeowner, or others wish to locate, map (e.g., bysurface position as defined by latitude/longitude or other surfacecoordinates, and/or also by depth), and/or provide a corresponding markof on the ground surface using paint or other markers.

The term “exemplary” as used herein means “serving as an example,instance, or illustration.” Any aspect, detail, function,implementation, and/or embodiment described herein as “exemplary” is notnecessarily to be construed as preferred or advantageous over otheraspects and/or embodiments

The measurements may be a vector, gradient, and/or combinedvector/gradient solution with magnitude, direction, and phasemeasurements for each frequency. Such a solution may include ameasurement of magnitude, direction, and/or phase at each frequency as afunction of both time and position. The simultaneously determined locatedata may be presented on a display or other output device separately foreach of two or more frequencies, may be presented in combination, suchas by using a single representation of locate data determined from aparticular suite or set of frequencies in a suite, and/or may be storedin a non-transitory memory or communicated to another locate systemdevice or remove system or device.

As described in further detail subsequently herein, processing ofreceived active and passive signals may be used to determine locationand/or depth of one or more utilities as well as other utilityinformation such as type of utility line detected within the ground,with the determined location and/or depth information based on aplurality of signals at different frequencies in either active frequencysuites, passive frequency suites, or combinations thereof.

Additional details of utility locator devices, transmitter devices, andother associated devices that may be used in embodiments in conjunctionwith the disclosures herein are described in co-assigned patent andpatent applications including: U.S. Pat. No. 7,009,399, issued Mar. 7,2006, entitled OMNIDIRECTIONAL SONDE AND LINE LOCATOR; U.S. Pat. No.7,136,765, issued Nov. 14, 2006, entitled A BURIED OBJECT LOCATING ANDTRACING METHOD AND SYSTEM EMPLOYING PRINCIPAL COMPONENTS ANALYSIS FORBLIND SIGNAL DETECTION; U.S. Pat. No. 7,221,136, issued May 22, 2007,entitled SONDES FOR LOCATING UNDERGROUND PIPES AND CONDUITS; U.S. Pat.No. 7,288,929, issued Oct. 30, 2007, entitled INDUCTIVE CLAMP FORAPPLYING SIGNAL TO BURIED UTILITIES; U.S. Pat. No. 7,298,126, issuedNov. 20, 2007, entitled SONDES FOR LOCATING UNDERGROUND PIPES ANDCONDUITS; U.S. Pat. No. 7,332,901, issued Feb. 19, 2008, entitledLOCATOR WITH APPARENT DEPTH INDICATION; U.S. Pat. No. 7,336,078, issuedFeb. 26, 2008, entitled MULTI-SENSOR MAPPING OMNIDIRECTIONAL SONDE ANDLINE LOCATORS; U.S. Pat. No. 7,498,797, issued Mar. 3, 2009, entitledLOCATOR WITH CURRENT-MEASURING CAPABILITY; U.S. Pat. No. 7,518,374,issued Apr. 14, 2009, entitled RECONFIGURABLE PORTABLE LOCATOR EMPLOYINGMULTIPLE SENSOR ARRAYS HAVING FLEXIBLE NESTED ORTHOGONAL ANTENNAS; U.S.Pat. No. 7,557,559, issued Jul. 7, 2009, entitled COMPACT LINEILLUMINATOR FOR LOCATING BURIED PIPES AND CABLES; U.S. Pat. No.7,619,516, issued Nov. 17, 2009, entitled SINGLE AND MULTI-TRACEOMNIDIRECTIONAL SONDE AND LINE LOCATORS AND TRANSMITTER USED THEREWITH;U.S. Pat. No. 7,741,848, issued Jun. 22, 2010, entitled ADAPTIVEMULTICHANNEL LOCATOR SYSTEM FOR MULTIPLE PROXIMITY DETECTION; U.S. Pat.No. 7,825,647, issued Nov. 2, 2010, entitled METHOD FOR LOCATING BURIEDPIPES AND CABLES; U.S. patent application Ser. No. 12/939,591, filedNov. 4, 2010, entitled SMART PERSONAL COMMUNICATION DEVICES AS USERINTERFACES; U.S. patent application Ser. No. 12/947,503, filed Nov. 16,2010, entitled IMAGE-BASED MAPPING LOCATING SYSTEM; U.S. Pat. No.7,863,885, issued Jan. 4, 2011, entitled SONDES FOR LOCATING UNDERGROUNDPIPES AND CONDUITS; U.S. Pat. No. 7,948,236, issued May 24, 2011,entitled ADAPTIVE MULTICHANNEL LOCATOR SYSTEM FOR MULTIPLE PROXIMITYDETECTION; U.S. Pat. No. 7,990,151, issued Aug. 2, 2011, entitledTRI-POD BURIED LOCATOR SYSTEM; U.S. Pat. No. 8,013,610, issued Sep. 6,2011, entitled HIGH Q SELF-TUNING LOCATING TRANSMITTER; U.S. patentapplication Ser. No. 13/356,408, filed Jan. 23, 2012, entitled SONDESAND METHODS FOR USE WITH BURIED LINE LOCATOR SYSTEMS; U.S. Pat. No.8,106,660, issued Jan. 31, 2012, entitled SONDE ARRAY FOR USE WITHBURIED LINE LOCATORS; U.S. patent application Ser. No. 13/493,883,issued Jun. 11, 2012, entitled MAGNETIC SENSING BURIED OBJECT LOCATORINCLUDING A CAMERA; U.S. Pat. No. 8,203,343, issued Jun. 19, 2012,entitled RECONFIGURABLE PORTABLE LOCATOR EMPLOYING MULTIPLE SENSOR ARRAYHAVING FLEXIBLE NESTED ORTHOGONAL ANTENNAS; U.S. patent application Ser.No. 13/570,211, filed Aug. 8, 2012, entitled PHASE SYNCHRONIZED BURIEDOBJECT LOCATOR APPARATUS, SYSTEMS, AND METHODS; U.S. patent applicationSer. No. 13/584,799, issued Aug. 13, 2012, entitled BURIED OBJECTLOCATOR SYSTEMS AND METHODS; U.S. patent application Ser. No.13/602,303, filed Sep. 3, 2012, entitled WIRELESS BURIED PIPE AND CABLELOCATING SYSTEMS; U.S. patent application Ser. No. 13/605,960, filedSep. 6, 2012, entitled SYSTEMS AND METHODS FOR LOCATING BURIED OR HIDDENOBJECTS USING SHEET CURRENT FLOW MODELS; U.S. Pat. No. 8,264,226, issuedSep. 11, 2012, entitled SYSTEM AND METHOD FOR LOCATING BURIED PIPES ANDCABLES WITH A MAN PORTABLE LOCATOR AND A TRANSMITTER IN A MESH NETWORK;U.S. patent application Ser. No. 13/676,989, filed Nov. 14, 2012,entitled QUAD-GRADIENT COILS FOR USE IN LOCATING SYSTEMS; U.S. patentapplication Ser. No. 13/677,223, filed Nov. 14, 2012, entitledMULTI-FREQUENCY LOCATING SYSTEMS AND METHODS; U.S. patent applicationSer. No. 13/793,168, filed Mar. 3, 2013, entitled BURIED OBJECT LOCATORSWITH CONDUCTIVE ANTENNA BOBBINS; U.S. patent application Ser. No.13/787,711, filed Mar. 6, 2013, entitled DUAL SENSED LOCATING SYSTEMSAND METHODS; U.S. patent application Ser. No. 13/841,879, filed Mar. 15,2013, entitled GROUND-TRACKING SYSTEMS AND APPARATUS; U.S. patentapplication Ser. No. 13/850,181, filed Mar. 25, 2013, entitled GRADIENTANTENNA COILS AND ARRAYS FOR USE IN LOCATING SYSTEMS; U.S. patentapplication Ser. No. 13/851,951, filed Mar. 27, 2013, entitled DUALANTENNA SYSTEMS WITH VARIABLE POLARIZATION; U.S. patent application Ser.No. 13/894,038, filed May 14, 2013, entitled OMNI-INDUCER TRANSMITTINGDEVICES AND METHODS; U.S. patent application Ser. No. 14/022,067, filedSep. 9, 2013, entitled USER INTERFACES FOR UTILITY LOCATORS; U.S. patentapplication Ser. No. 14/080,582, filed Nov. 14, 2013, entitledMULTI-FREQUENCY LOCATING SYSTEMS AND METHODS; U.S. Pat. No. 8,547,428,issued Oct. 1, 2013, entitled PIPE MAPPING SYSTEM; U.S. patentapplication Ser. No. 14/053,401, filed Oct. 14, 2013, entitled BURIEDOBJECT LOCATING DEVICES AND METHODS; U.S. patent application Ser. No.14/148,649, filed Jan. 6, 2014, entitled MAPPING LOCATING SYSTEMS ANDMETHODS; U.S. patent application Ser. No. 14/154,128, filed Jan. 13,2014, entitled UTILITY LOCATOR SYSTEMS AND METHODS; U.S. patentapplication Ser. No. 14/179,538, filed Feb. 12, 2014, entitled OPTICALGROUND TRACKING APPARATUS, SYSTEMS, AND METHODS; U.S. patent applicationSer. No. 14/207,502, filed Mar. 12, 2014, entitled GRADIENT ANTENNACOILS AND ARRAYS FOR USE IN LOCATING SYSTEMS; U.S. patent applicationSer. No. 14/210,251, filed Mar. 13, 2014, entitled MULTI-FREQUENCYLOCATING SYSTEMS AND METHODS; U.S. patent application Ser. No.14/215,290, filed Mar. 17, 2014, entitled SONDE DEVICES INCLUDING ASECTIONAL FERRITE CORE; U.S. patent application Ser. No. 14/229,813,filed Mar. 28, 2014, entitled UTILITY LOCATOR TRANSMITTER APPARATUS ANDMETHODS; U.S. patent application Ser. No. 14/321,699, filed Jul. 1,2014, entitled UTILITY LOCATOR APPARATUS, SYSTEMS, AND METHODS; U.S.Pat. No. 8,773,133, issued Jul. 8, 2014, entitled ADAPTIVE MULTICHANNELLOCATOR SYSTEM FOR MULTIPLE PROXIMITY DETECTION; U.S. patent applicationSer. No. 14/332,268, filed Jul. 15, 2014, entitled UTILITY LOCATORTRANSMITTER DEVICES, SYSTEMS, AND METHODS WITH DOCKABLE APPARATUS; U.S.patent application Ser. No. 14/446,279, filed Jul. 29, 2014, entitledINDUCTIVE CLAMP DEVICES, SYSTEMS, AND METHODS; U.S. patent applicationSer. No. 14/516,558, filed Oct. 16, 2014, entitled ELECTRONIC MARKERDEVICES AND SYSTEMS; U.S. patent application Ser. No. 14/580,097, filedDec. 22, 2014, entitled NULLED-SIGNAL LOCATING DEVICES, SYSTEMS, ANDMETHODS; U.S. patent application Ser. No. 14/584,996, filed Dec. 29,2014, entitled OPTICAL GROUND TRACKING METHODS AND APPARATUS FOR USEWITH BURIED UTILITY LOCATORS; U.S. Provisional Patent Application62/107,985, filed Jan. 26, 2015, entitled SELF-STANDING MULTI-LEGATTACHMENT DEVICES FOR USE WITH UTILITY LOCATORS; U.S. Pat. No.9,041,794, issued May 26, 2015, entitled PIPE MAPPING SYSTEMS ANDMETHODS; U.S. Pat. No. 9,057,754, issued Jun. 16, 2015, entitledECONOMICAL MAGNETIC LOCATOR APPARATUS AND METHOD; U.S. patentapplication Ser. No. 14/752,834, filed Jun. 27, 2015, entitled GROUNDTRACKING APPARATUS, SYSTEMS, AND METHODS; U.S. Pat. No. 9,081,109,issued Jul. 14, 2015, entitled GROUND-TRACKING DEVICES FOR USE WITH AMAPPING LOCATOR; U.S. Pat. No. 9,082,269, issued Jul. 14, 2015, entitledHAPTIC DIRECTIONAL FEEDBACK HANDLES FOR LOCATION DEVICES; U.S. patentapplication Ser. No. 14/800,490, filed Jul. 15, 2015, entitled UTILITYLOCATOR TRANSMITTER DEVICES, SYSTEMS, AND METHODS WITH SATELLITE ANDMAGNETIC FIELD SONDE ANTENNA SYSTEMS; U.S. Pat. No. 9,085,007, issuedJul. 21, 2015, entitled MARKING PAINT APPLICATOR FOR PORTABLE LOCATOR;U.S. Provisional Patent Application 62/244,658, filed Oct. 21, 2015,entitled SIGNAL KEYING UTILITY LOCATING DEVICES, SYSTEMS, AND METHODS;U.S. patent application Ser. No. 14/949,868, filed Nov. 23, 2015,entitled BURIED OBJECT LOCATOR APPARATUS AND SYSTEMS; U.S. ProvisionalPatent Application 62/260,199, filed Nov. 25, 2015, UTILITY LOCATINGSYSTEMS, DEVICES, AND METHODS USING RADIO BROADCAST SIGNALS. The contentof each of the above-described applications is hereby incorporated byreference herein in its entirety. The above applications may becollectively denoted herein as the “co-assigned applications” or“incorporated applications”.

In one aspect, the systems, methods, and devices of the presentdisclosure may receive and measure magnetic field signals resulting fromcurrent flow in a buried utility at fundamental frequencies and harmonicfrequencies simultaneously and independently. The multiple frequencysignals may be from one or more active and/or passive signals. Thesignals may be collected within a suite of two or more signals. In anexemplary embodiment a suite includes fundamentals and harmonics orother signals related by integer factors. Each fundamental frequency andharmonic frequency thereof may be simultaneously and individuallymeasured by a utility locator to produce a vector, gradient, and/orcombined vector/gradient solution for each determined location and depthof a utility or utilities within the ground. For example, two or moresolutions for a determined depth may be determined simultaneously andindependently for a power line signal at 60 Hz and one or more of itsharmonics (or, omitting the fundamental at 60 Hz, two or more harmonicsmay be used to independently determine depth, vector, gradient, or otherinformation about the utility).

Such a solution may include a measurement of magnitude, direction,and/or phase at each frequency as a function of both time and position.The simultaneously determined locate data may be presented on a displayor displays separately for each of two or more frequencies, may bepresented in combination, such as by using a single representation oflocate data determined from a particular suite or set of frequencies ina suite, and/or may be stored in a non-transitory memory or communicatedto another locate system device or remove system or device for remoteanalysis, display/rendering, printing, and/or storage.

In another aspect, the systems, devices, and methods herein may use acomparison of solutions at different geographical locations within thelocate operation to allow for a refined determination of location,depth, and/or type of utility/utilities and/or other conductors. In someembodiments, the comparison may be or may include principal componentanalysis (PCA), independent component analysis (ICA), and/or othercomponent analysis or correlation methods as are known or developed inthe art.

In another aspect, systems, methods, and devices of the presentdisclosure may be tuned to receive and process magnetic field signals atpower line frequencies (e.g., 50 or 60 Hz, or other AC power frequenciesas may be used in alternate power supply systems) and harmonics thereof.

In another aspect, systems, methods, and devices of the presentdisclosure may be processed in conjunction with the locator receiverprocessing and/or other processing being phase locked to an AC powergrid or other frequency reference.

In another aspect, systems, methods, and devices of the presentdisclosure may process received signals to separate out odd and evenharmonics magnetic field signals (e.g., such as odd and even harmonicsof power line signals or other signals flowing in a hidden or buriedconductor/utility). Ratios of odd and even harmonic frequencies may beused, such as through ratios, spectral signatures, and other processingmechanisms to determine location, depth, and/or utility type.

In another aspect, systems, devices, and methods herein may usepredetermined sets and groupings of harmonics in frequency suites, whichmay be used to determine location, depth, and/or utility type.

In another aspect, systems, devices, and methods herein may usecorrelations/patterns of harmonics to refine location, depth, and/orutility type.

In another aspect, systems, devices, and methods herein may measurephase of one or more signals. In some such embodiments, relative and/orabsolute phase may be determined with respect to reference phases at aphase reference point or at or relative to a locate position or otherreference.

In another aspect, systems and devices herein may implement methods foradjusting filter bandwidth and/or averaging of filter output signals inutility locator signal processing circuitry based upon movement of theutility locator and/or other criteria determined during a locateoperation.

In another aspect, systems, devices, and methods herein may perform aninitial spectral scan of a locate area and/or utilize prior spectralscan data within a current locate operation to compare with presentand/or additional spectral scan data.

In another aspect, systems, devices, and methods described herein may beused in mapping of utility lines and systems, such as in combinationwith utility mapping embodiments described in the incorporatedapplications.

In another aspect the disclosure relates to a buried utility locator.The locator may include, for example, an antenna array for receivingmagnetic field signals from a buried utility in two or more orthogonaldirections, the antenna array having a bandwidth including a pluralityof predefined signal frequencies in a predefined first frequency suite,a receiver operatively coupled to the antenna array for generating areceiver output signal including amplitude and/or phase information offirst two or more signal components in two or more simultaneouslyreceived signals of the first frequency suite, a processing elementoperatively coupled to the receiver for receiving the receiver outputsignal and generating a first set of data associated with the two ormore signal components of the first frequency suite, a non-transitorymemory for storing the first set of data, and a display to render avisual output corresponding to the determined first set of data.

The first frequency suite may, for example, be a passive frequency suiteincluding signal components at two or more passive frequencies, and thefirst set of data may be based on the two or more passive frequencysignal components. The first frequency suite may be active frequencysuite including signal components at two or more active frequencies, andthe first set of data is may be based on the two or more activefrequency signal components. The first frequency suite may include asignal component at a passive frequency and a signal component at anactive frequency, and the first set of data may be based on the passivefrequency signal component and the active frequency signal component.

The antenna array may, for example, have a bandwidth that includes asecond plurality of frequencies in a second frequency suite, thereceiver may generate the output signal to include second two or moresignal components in two or more frequencies in the second frequencysuite, the processing element may generate a second set of dataassociated with the second two or more signal components, and the secondset of data may be stored in the non-transitory memory.

The first frequency suite may, for example, be an active frequency suiteincluding signal components at two or more active frequencies, and thefirst set of data may be based on the two or more active frequencysignal components. The first frequency suite may be an active frequencysuite including signal components at two or more active frequencies, andthe first set of data may be based on the two or more active frequencysignal components.

The second frequency suite may, for example, be a passive frequencysuite including signal components at two or more passive frequencies,and the second set of data may be based on the two or more passivefrequency signal components.

The first frequency suite may, for example, include a signal componentat a passive frequency and a signal component at an active frequency,and the first set of data may be based on the passive frequency signalcomponent and the active frequency signal component.

The second frequency suite may, for example, include a signal componentat a passive frequency and a signal component at an active frequency,and the second set of data may be based on the passive frequency signalcomponent and the active frequency signal component.

The information associated with the buried utility may, for example, bebased on the two or more signal components of the first frequency suiteis rendered on the display.

The locator may for example, further include a module for generatingpositional information of the locator, wherein the positionalinformation of the locator is associated with the two or more signalcomponents and stored in the non-transitory memory. The module forgenerating positional information may be a GPS or other satellite orterrestrial receiver module and the positional information is latitudeand longitude information. The module may be an inertial sensing module.

The generated data associated with the two or more signal components ofthe first frequency suite may, for example, include separate depthinformation of the buried utility determined based on ones of the two ormore signal components. The generated data associated with the two ormore signal components of the first frequency suite may include separatepositional information of the buried utility relative to the locatordetermined based on ones of the two or more signal components. Thegenerated data associated with the first two or more signal componentsand the second two or more signal components may include separate depthinformation of the buried utility determined based on ones of the firsttwo or more signal components and ones of the second two or more signalcomponents. The generated data associated with the first two or moresignal components and the second two or more signal components mayinclude separate position information of the buried utility determinedbased on ones of the first two or more signal components and ones of thesecond two or more signal components. The process of generating dataassociated with the two or more signals of the plurality of frequenciesmay include generating the data using a discrete Fourier transform (DFT)on the receiver output signal to extract amplitude and/or phaseinformation from ones of the signals of the plurality of frequencies.

The plurality of frequencies of the first frequency suite may, forexample, be passive signals based on a fundamental and/or harmonics of apower line frequency. The power line frequency may be 50 Hz or 60 Hz.The plurality of frequencies of the first frequency suite may be activesignals based on a fundamental and/or harmonics of a utility transmitteroutput signal directly or inductively coupled to the buried utility.

The first set of data associated with the two or more signal componentsmay, for example, be associated with a first utility of the one or moreburied utilities, and the first set of data may be presented on thedisplay as a single linear element corresponding to the first utility.The data from the first set of data may be averaged or otherwisecombined to generate the single linear element on the display. Thedisplay may include a rendered map or image of the locate area and thetwo or more linear elements may be superimposed on the map. The map maybe a raster or vector based map or may be another image or graphicrepresenting the locate area.

The first set of data associated with the two or more signal componentsmay be associated with a first utility of the one or more buriedutilities, and the first set of data may be presented on the display astwo or more separate linear elements corresponding to a representationof the utility based on simultaneously received and processed datacorresponding to the two or more signal components. The display mayinclude a rendered map or image of the locate area and the two or morelinear elements may be superimposed on the map. The map may be a rasteror vector based map or may be another image or graphic representing thelocate area.

The first set of data associated with the two or more signal componentsmay be associated with a first utility of the one or more buriedutilities, the second set of data associated with the second two or moresignal components may be associated with a second utility of the one ormore buried utilities, the first set of data may be presented on thedisplay as one or more linear elements corresponding to the firstutility, and the second set of data may be presented on the display asone or more linear elements corresponding to the second utility. Thedisplay may include a rendered map or image of the locate area and thetwo or more linear elements may be superimposed on the map. The map maybe a raster or vector based map or may be another image or graphicrepresenting the locate area.

A spectral signature may, for example, be determined from the first setof data, and a first utility type may be determined based on comparisonof the determined spectral signature and a reference spectral signature.The first utility type may be determined to be a water line. The firstutility type may be determined to be an AC power line.

In another aspect, the disclosure relates to a method for locatingburied utilities. The method may include, for example, receiving, at anantenna array for receiving magnetic field signals from a buried utilityin two or more orthogonal directions, a plurality of magnetic fieldsignals at predefined signal frequencies in a predefined first frequencysuite, generating, in a receiver coupled to an output of the antennaarray, a receiver output signal including amplitude and/or phaseinformation of first two or more signal components in two or moresimultaneously received signals of the first frequency suite,generating, in a processing element coupled to the receiver, a first setof data associated with the two or more signal components of the firstfrequency suite, storing, a non-transitory memory of the locator, thefirst set of data, and rendering, on a display of the locator, a visualoutput corresponding to the determined first set of data.

The first frequency suite may, for example, be a passive frequency suiteincluding signal components at two or more passive frequencies, and thefirst set of data may be based on the two or more passive frequencysignal components. The first frequency suite may be active frequencysuite including signal components at two or more active frequencies, andthe first set of data is may be based on the two or more activefrequency signal components. The first frequency suite may include asignal component at a passive frequency and a signal component at anactive frequency, and the first set of data may be based on the passivefrequency signal component and the active frequency signal component.

The antenna array may, for example, have a bandwidth that includes asecond plurality of frequencies in a second frequency suite, thereceiver may generate the output signal to include second two or moresignal components in two or more frequencies in the second frequencysuite, the processing element may generate a second set of dataassociated with the second two or more signal components, and the secondset of data may be stored in the non-transitory memory.

The first frequency suite may, for example, be an active frequency suiteincluding signal components at two or more active frequencies, and thefirst set of data may be based on the two or more active frequencysignal components. The first frequency suite may be an active frequencysuite including signal components at two or more active frequencies, andthe first set of data may be based on the two or more active frequencysignal components.

The second frequency suite may, for example, be a passive frequencysuite including signal components at two or more passive frequencies,and the second set of data may be based on the two or more passivefrequency signal components.

The first frequency suite may, for example, include a signal componentat a passive frequency and a signal component at an active frequency,and the first set of data may be based on the passive frequency signalcomponent and the active frequency signal component.

The second frequency suite may, for example, include a signal componentat a passive frequency and a signal component at an active frequency,and the second set of data may be based on the passive frequency signalcomponent and the active frequency signal component.

The information associated with the buried utility may, for example, bebased on the two or more signal components of the first frequency suiteis rendered on the display.

The method may further include generating positional information of thelocator, wherein the positional information of the locator is associatedwith the two or more signal components and stored in the non-transitorymemory. The module for generating positional information may be a GPS orother satellite or terrestrial receiver module and the positionalinformation is latitude and longitude information. The module may be aninertial sensing module.

The generated data associated with the two or more signal components ofthe first frequency suite may, for example, include separate depthinformation of the buried utility determined based on ones of the two ormore signal components. The generated data associated with the two ormore signal components of the first frequency suite may include separatepositional information of the buried utility relative to the locatordetermined based on ones of the two or more signal components. Thegenerated data associated with the first two or more signal componentsand the second two or more signal components may include separate depthinformation of the buried utility determined based on ones of the firsttwo or more signal components and ones of the second two or more signalcomponents. The generated data associated with the first two or moresignal components and the second two or more signal components mayinclude separate position information of the buried utility determinedbased on ones of the first two or more signal components and ones of thesecond two or more signal components. The process of generating dataassociated with the two or more signals of the plurality of frequenciesmay include generating the data using a discrete Fourier transform (DFT)on the receiver output signal to extract amplitude and/or phaseinformation from ones of the signals of the plurality of frequencies.

The plurality of frequencies of the first frequency suite may, forexample, be passive signals based on a fundamental and/or harmonics of apower line frequency. The power line frequency may be 50 Hz or 60 Hz.The plurality of frequencies of the first frequency suite may be activesignals based on a fundamental and/or harmonics of a utility transmitteroutput signal directly or inductively coupled to the buried utility.

The first set of data associated with the two or more signal componentsmay, for example, be associated with a first utility of the one or moreburied utilities, and the first set of data may be presented on thedisplay as a single linear element corresponding to the first utility.The data from the first set of data may be averaged or otherwisecombined to generate the single linear element on the display. Thedisplay may include a rendered map or image of the locate area and thetwo or more linear elements may be superimposed on the map. The map maybe a raster or vector based map or may be another image or graphicrepresenting the locate area.

The first set of data associated with the two or more signal componentsmay be associated with a first utility of the one or more buriedutilities, and the first set of data may be presented on the display astwo or more separate linear elements corresponding to a representationof the utility based on simultaneously received and processed datacorresponding to the two or more signal components. The display mayinclude a rendered map or image of the locate area and the two or morelinear elements may be superimposed on the map. The map may be a rasteror vector based map or may be another image or graphic representing thelocate area.

The first set of data associated with the two or more signal componentsmay be associated with a first utility of the one or more buriedutilities, the second set of data associated with the second two or moresignal components may be associated with a second utility of the one ormore buried utilities, the first set of data may be presented on thedisplay as one or more linear elements corresponding to the firstutility, and the second set of data may be presented on the display asone or more linear elements corresponding to the second utility. Thedisplay may include a rendered map or image of the locate area and thetwo or more linear elements may be superimposed on the map. The map maybe a raster or vector based map or may be another image or graphicrepresenting the locate area.

A spectral signature may, for example, be determined from the first setof data, and a first utility type may be determined based on comparisonof the determined spectral signature and a reference spectral signature.The first utility type may be determined to be a water line. The firstutility type may be determined to be an AC power line.

The combined passive and active locating devices, systems, and methodsherein may be used in mapping utility lines and/or other like assets.

In another aspect, the disclosure relates to means for implementing theabove devices and methods.

In another aspect, the disclosure relates to non-transitory computermedium including instructions for use by a processing element toimplement the above-described methods, in whole or in part.

Various additional aspects, features, and functions are described belowin conjunction with FIGS. 1A through 20B of the appended Drawings.

It is noted that the following exemplary embodiments are provided forthe purpose of illustrating examples of various aspects, details, andfunctions of apparatus, methods, and systems for locating buried orhidden objects; however, the described embodiments are not intended tobe in any way limiting. It will be apparent to one of ordinary skill inthe art that various aspects may be implemented in other embodimentswithin the spirit and scope of the present disclosure.

EXAMPLE EMBODIMENTS

At any given time, a user doing a traditional locate operation (i.e., auser walking around over a ground surface with a utility locator insearch of buried utilities) uses either active signals or passivesignals for finding buried utilities, but typically not both at the sametime or in conjunction with each other. Likewise, traditional locateoperations typically use only a single signal at a single frequency atany given time. However, as described herein, additional potentialsignal detection and processing functionality can be used by combinedsimultaneous processing of both types of signals to synergisticallyimprove locate performance and/or by combined simultaneous processing offundamental signals and their harmonics.

Combined passive and active locating system embodiments in accordancewith aspects of the present disclosure may include a utility locator forsimultaneously receiving and processing magnetic field signal componentsemitted from a buried utility at multiple frequencies. Such signals mayinclude magnetic field signals resulting from currents intentionallyimpressed on a utility line from a transmitter device (“active signals”)as well as magnetic field signals resulting from currents incidentallyinduced onto utility lines by signal generators in the locateenvironment (“passive signals”).

System embodiment 100 of FIG. 1A illustrates one example locate system.System 100 may include a utility locator 110 to receive and processmagnetic field signals generated by currents impressed upon utilitylines 120 and/or 130 by a locate transmitter device 140. A locatetransmitter, or simply “transmitter” for brevity, is a device thatgenerates current signals that can be either directly coupled to autility, such as with conductive clamps or contact clips, or inductivelycoupled to the utility using an inductive coil antenna or otherinductive device.

Currents flowing in utility lines 120 and/or 130 may also be inducedfrom the magnetic fields generated by overhead power lines 150 and/orother passive or active signal generating elements, such as broadcastradio transmitters, etc. (not illustrated). The currents generatepassive magnetic field signals that can likewise be detected andprocessed by locator 110.

Other system embodiments may include various additional devices. Forexample, additional system embodiments may include, but are not limitedto, base stations, tablet computers, smart phones, other computingdevices, mapping systems and devices, pipe sondes (for generatingmagnetic field dipole signals), and/or other pipe inspection devices.Although magnetic field signals are typically received and processed inlocator 110, in some system and device embodiments, processing ofsignals received by locator 110 may in part or in full be implemented ina processing element of one or more devices separate from the locator,such as a laptop computer communicatively coupled to the locator, acloud based computing system, or other local or remote processingelements.

Processing of received magnetic field signals at multiple frequenciesmay be used to generate an individual vector solution or gradientsolution or combined vector/gradient solution for the differentfrequencies within the received signals set. Such a solution may includemeasurements at each frequency providing a magnitude, direction, and/ormeasurement of relative and/or absolute phase of the signal receivedfrom the buried utility and may be based on simultaneous receipt and/orprocessing of multiple signals at different frequencies.

Processing of the received signal may include use of principal componentanalysis (PCA), independent component analysis (ICA), and/or othercomponent analysis or correlation methods. An example of such method isdisclosed in co-assigned U.S. Pat. No. 7,136,765, filed Aug. 15, 2005,entitled A BURIED OBJECT LOCATING AND TRACING METHOD AND SYSTEMEMPLOYING PRINCIPAL COMPONENTS ANALYSIS FOR BLIND SIGNAL DETECTION, thecontent of which is incorporated by reference herein in its entirety.

Utility locator 110, as well as other utility locator device embodimentsin accordance with the present disclosure, may be tuned to receive andmeasure signals at multiple frequencies simultaneously. For example, inan exemplary embodiment a discrete Fourier transform (DFT), or multipleparallel receiver channels, and/or other filtering techniques may beused to process and measure received magnetic field signals at multiplefrequencies simultaneously. In an exemplary embodiment these frequenciesmay include one or more fundamental frequencies and a selection ofharmonic frequencies thereof. The frequencies may be from active signalsresulting from currents intentionally impressed upon a utility lineand/or passive signals resulting from currents incidentally impressedupon a utility and/or other conductor(s).

For example, locator 110 of FIG. 1A may be tuned to measure afundamental frequency/frequencies of a magnetic field signal resultingfrom a current signal or signals generated and coupled to the utilityfrom the transmitter device 140, and as well as various harmonicfrequencies thereof. The locator 110 may further be tuned to measure thefundamental frequency/frequencies and various harmonic frequencies ofone or more passive signals emitted from the utility as a result ofpassively coupled currents flowing therein. Such passive signal(s) mayinclude, for example, a 60 Hz fundamental frequency of power lines 150as well as one or more of its harmonic frequencies (e.g., at one or moreof 120 Hz, 180 Hz, 240 Hz, 300 Hz, etc.).

Some utility locator embodiments, such as locator 110 of FIG. 1A, may bephase synchronized with the power grid or with some other referencesignal. For example, phase may be synchronized between the utilitylocator 110 and the measured 60 Hz fundamental of the nearby powerlines, as well as the utility locator 110 and each harmonic frequency(the phase of harmonics of the fundamental may be shifted for variousreasons, such as impedance of the utility circuit, etc.).

FIG. 1B illustrates an exemplary method embodiment 160 for phasesynchronization. As illustrated in method 160, phase may be synchronizedwith induced signals from an AC power grid such as a 50 Hz or 60 Hzpower distribution network. At step 165, magnetic field signals emittedfrom a utility (e.g., from a passively induced 60 Hz current) may bereceived at the utility locator. In step 170, a discrete Fouriertransform (DFT), FFT, and/or other filtering methods may be used todetermine information about harmonics of the AC power, such as amplitudeand phase. In step 175, the highest harmonic with a pre-determinedmeasured signal magnitude above a threshold may be selected (e.g., basedon a hard threshold signal value or adaptive threshold value). Such athreshold may, for example, be determined by the measured relativestrength of signal at that particular harmonic frequency and/or may bedetermined by the user, either statically or dynamically. In otherembodiments, other criteria for determining such a threshold may beused, such as selecting a predefined amplitude threshold orsignal-to-noise ratio threshold or other signal metric. The selectedharmonic may be predetermined/preset within the utility locator, withoutinput from a user, in some embodiments.

In step 180, a software phase-locked loop (PLL) may be used to determinea precise frequency and phase of the signal at the selected harmonic. Instep 185, the DFT tuning for all harmonics may be adjusted based on thefrequency and phase parameters determined in step 180. The DFT may beimplemented continuously, periodically, or in some embodimentsasynchronously, such as on device or user demand.

In some utility locator device embodiments, measured frequencies may bedivided amongst different frequency suites, with each frequency suiteincluding a set of two or more frequencies. For example, chart 190 ofFIG. 1C shows an embodiment having seven different frequency suites,with each suite having six different frequencies. The frequency suitesmay include frequencies from one or more passive signals, such as thepassive signal suites 192 selected based on 60 Hz power harmonics (e.g.,60 Hz signals induced in a buried conductive utility from overhead 60 Hzpower lines), and/or one or more active signals, such as the activesignal frequency suite 194 based on a utility transmitter coupledcurrent signal and its associated harmonics. In some embodiments, afrequency suite may include frequencies from both passive and activesignals within the same frequency suite (not illustrated in FIG. 1C).With passive frequency suites, the selected frequencies may be related(e.g., as harmonics of fundamental AC power frequencies or otherenvironmentally induced signals) or may be a selection of unrelated orarbitrarily chosen frequencies (e.g., an AC power fundamental, aharmonic of the AC power falling in a band of particular interest (e.g.,the 10^(th) or 15^(th) harmonic), an induced broadcast radio frequency,other unrelated induced signal frequencies, etc.). For passive suites inparticular, the suite may be simply a list of frequencies that maycontain one or more signal components of interest that are notintentionally induced (e.g., through use of a transmitter or otherinduction device as an “active” signal). Passive frequency suites thatinclude a set of frequencies that are not related may also be denotedherein as a “passive frequency group.” Passive frequency groups are justlists of two or more passive frequencies where magnetic field signalsmay be present, with the magnetic field signals resulting from currentsflowing in the utility as a result of environmental conditions and notactive coupling by a user.

In a typical operation, the frequency component signals of an activesuite are all coupled (initially) to a particular utility or utilitiesat a single point, whereas the passive signals can come from anywhere inthe environment. Active signals can cross-coupled to other utilities orother conductors in the environment once they are coupled initially, andthis coupling is typically a function of frequency, which results indifferent measurement information at the locator as the user's positionchanges due to phase and amplitude changes to the coupled signals due tothe particular locate environment structure and parameters (e.g.,utilities or other conductors present and cross-coupling therebetween,soil conditions and impedance/conductivity, above-ground structures,etc.).

In various embodiments, targeted frequencies may be distributed amongstone or more frequency suites. For example, FIG. 1B illustrates sixpassive frequency suites 192 and one active frequency suite 194. Thefrequencies within the six passive frequency suites 192 include the 60Hz fundamental power line frequency and harmonics thereof distributedthroughout frequency suites 1 through 6 (assuming that 60 Hz powersignals are induced from a power line or other AC power source in theproximity of the locate site). Frequency suite 7 includes signalfrequencies that result from currents that are actively generated in atransmitter and coupled directly or inductively to the utility.

In other embodiments, various frequency suites may contain bothfundamental and/or harmonic frequencies from various passive and/oractive signals, either separated or combined. Utility locator deviceembodiments may, for example, have thirty two separate frequency suiteseach containing six frequencies. In other embodiments, any number offrequencies may be contained within each frequency suite, and thefrequencies which may also be distributed in various ways amongst anynumber of frequency suites and/or be selectable/customizable by theuser, such as through a user interface on the locator or via apre-locate setup interface on or coupled to the locator to allow a userto set the locator up for operation at a particular locate site.

Utility locators disclosed herein, such as locator 110 of FIG. 1A, mayalso include mapping and/or location tracking sensors and systems suchas global navigation satellite systems (GNSS, GPS), inertial navigationsystems (INS), optical navigation systems/sensors and/or motion trackingsensors. Examples of utility locator embodiments with suchsensors/systems are disclosed in various incorporated applications.

FIG. 2 illustrates a method embodiment 200 using a utility locatorincluding a position sensing module for determining and storing itslocation (e.g., a GPS receiver, inertial sensor, etc.). In step 210, theutility locator may simultaneously receive and measure signals at eachfundamental and a selection of harmonic frequencies thereof based on oneor more frequency suites. Such measurements may include a vector,gradient, and or combined vector/gradient solution at each frequency,containing a magnitude and direction as well as an absolute and/orrelative phase measurement, which may further be associated with theutility locator's determined geographical location (e.g., through use ofa GPS receiver or other positional determination module) and stored in anon-transitory memory.

In step 220, the individual signal measurements may be used to determinelocation, depth, and/or utility type corresponding to the locator'slocation based on the device's mapping and/or location tracking sensorsand systems. Various method embodiments for determining utilityinformation are described subsequently herein in conjunction with FIGS.11-17. In step 230, the measured signal data from step 210 and/ordetermined utility information from step 220 may be stored in anon-transitory memory in the locator device.

A decision may be made in step 240 as to whether the utility locateoperation is completed (i.e., the user is finished doing a locateoperation in the area). If the locate operation is finished, themeasured signal data and/or determined utility locate information storedat step 230 may optionally be communicated to other system devices, suchas mapping systems and/or other local or remote systems or centralizeddatabase(s), at step 250. In some embodiments, such information maycontinually and/or periodically be communicated to other systems/devicesthroughout the utility locating process, such as through WiFiconnections, cellular data connections, or other wired or wirelesscommunication connections and associated modules in the locator andremote system. Alternately, or in addition, the information may becollected and stored onsite in the locator or an associated device, suchas a tablet, cellular phone, laptop computer, and the like, for laterprocessing.

Returning to step 240, if the utility locate operation has not beencompleted, in step 260 the utility locator may then be moved (e.g., byhaving the user walk further around the locate area/continue locatingoperation). Method 200 may then be repeated at step 210. In some methodembodiments, successive iterations may utilize prior signal measurementand/or determined utility information to refine future locating data.

FIG. 3 illustrates details of a locator graphical user interface (GUI)display embodiment 300 in accordance with aspects of the presentdisclosure. The GUI may be used for providing locate-related informationto the user during the locate operation as well as for receiving inputfrom a user to control locator operation. The display 300 may show thedetermined location of utility lines, such as through displayed lines310 and 320 as oriented on a map 330 or other representation of thelocate area. In an exemplary embodiment, the representation of utilitylines 310 and 320 may be based on signal data determined simultaneouslyat multiple frequencies from multiple signal components within one ormore frequency suites.

As is known in the art, locate information, such as position of theutility, depth of the utility, and orientation of the utility relativeto the locator (in two or three-dimensional space) is typicallydetermined in existing locators based only on measurements of magneticfield signals at a single frequency at a given time. However, separatedeterminations of locate parameters may be made simultaneously on two ormore frequencies in a suite of frequencies by separating out the variouscomponent frequency signals by, for example, use of a DFT or otherfrequency-selective filter, and performing locate calculationssimultaneously on each of the signal frequency components.

The individual frequency component results may be aggregated in variousways to provide a composite output or multiple discrete outputs. Forexample, the determined locate data (e.g., position, depth, currentmagnitude, orientation, phase angle, etc.) may be averaged or otherwisecombined (e.g., by thresholding, weighted averaging, or other techniquesas known or developed in the art for combining multiple samples into oneor more results) based on separate determinations from two or morefrequencies in a suite, or from frequencies in different suites, or fromcombinations thereof. Separate suites of active and passive frequencysignals and correspondingly determined data may be associated, combined,displayed, and/or stored in a non-transitory memory of the locator orother associated device.

For example, in one embodiment, information from signals received andprocessed from signals in frequencies in multiple frequency suites maybe rendered as a single displayed line on display 300. This may be doneseparately for each utility line present, such as for separate utilitylines 310 and 320. As shown in FIG. 3, lines 310 or 320 may be renderedon the display to represent two separate utilities beneath the ground asdetermined by the utility locator, with each of the lines presentedbased on data from utility data calculations (e.g., position, depth,current magnitude, orientation, phase angle, etc.) make from two or moredifferent frequency signal components. In one embodiment, one or more ofthe signal components may be from an active frequency signal component,while one or more others may be from a passive frequency signalcomponent. In some embodiments both types of signal components may bepresent on one or more of the targeted utilities, such as for utilitieswhere passive signals have been induced thereon (e.g., by nearby ACpower lines) as well as active signals that are directly or inductivelycoupled from a utility locator transmitter. By measuring multiple signalcomponents at separated frequencies, better locate information may beobtained than from use of a single frequency magnetic field signal as itused in traditional locators.

Lines 310 and 320 of FIG. 3 may be superimposed onto a map 330, whichmay be generated from map data or imagery stored or collected in theutility locator and/or other map system or other representation of thelocate area. For example, map data may be stored in the locator such asis done in common devices like automotive GPSs and the like, and/or mapdata may be downloaded from a remote site to the locator via a wired orwireless connection, or may be loaded from a memory device such as USBthumb drive or memory card. Map data may be in either vector or rasterformat, and may include graphics, line drawings, photographic images,video, or other image or graphics types.

Each utility line may be visually distinguished from each other on thedisplay. For example, lines 310 and 320 may be distinguished bydifferent patterns and/or colors on the display 300 and/or by shading,dashing or different line types, and the like. Different indicators ofutility type, such as utility type indicators 312, 314, 322, and/or 324may be used to present a particularly determined utility type visuallyto the user. Utility type may be determined by, for example, selecting aparticular active frequency or frequency suite to be applied to theparticular type of utility from a coupled utility transmitter or byother utility type identification methods such as those described in theincorporated applications. Individual frequencies and/or information onfrequency suites used in determining the utility lines may also beprovided on the locator display, such as through a visual list, colorcode, or other representation on the display. Likewise, the determinedutility data may be associated with and stored with particular frequencyor frequency suite information used to determine the data.

A visual metric or icon representing utility depth, such as depth gauges316 and 326, may be displayed, corresponding to a determined depth ofeach line 310 and 320 (based on data generated by processing magneticfield signals of multiple frequency components in one or more frequencysuites or groups). Additional visual indications of the relative depthof the utility or utilities may also be included. For example, linewidth variations, such as a shortening of line 320 within concentriccircle 340, may be used to determine its depth relative to line 310and/or depth relative to the ground's surface. Various other display andindication methods, such as those described in the various incorporatedapplications or otherwise known or developed in the art, may also beused in various embodiments.

Display 300 may include additional gauges and/or indicators. Forexample, a battery gauge 350 may be included to indicate available powerleft for the utility locator's battery. Examples of batteries andassociated devices and gauging as may be used in such a locator aredescribed in the incorporated applications. If other locate systemdevices are used during a locate operation, additional battery gauges352, 354, and 356 may be provided on the display to show the batterypower of other communicatively coupled system devices (e.g., utilitylocate transmitters, paint marking devices, video camera systems andcamera control units, and the like). Additional indicators, such aGlobal Navigation Satellite System (GNSS) connectivity indicator 360,Bluetooth connectivity indicator 370, and wireless local area network(WLAN) connectivity indicator 380 may be provided on the display toindicate status of such sensors/systems within and/or connected to theutility locator.

In other embodiments, additional information may be conveyed by agraphical interface such as the display 300 of FIG. 3, such as thevarious display information illustrated in the incorporatedapplications. A utility locator may further provide information in otherways besides graphical interface including, but not limited to, textualinformation, visible light indicators, audible indicators, hapticfeedback indicators, and/or other user interface or data presentationdevices as known or developed in the art.

In some utility locator embodiments, a locator display may be providedto allow a user to toggle between various screens to show different setsof information. For example, one such screen may display frequenciesused within each individual frequency suite or may show frequencies frommultiple frequency suites. One example of this is illustrated in FIG. 4,where display 400 shows a passive signal frequency suite 1, representedas element 405, comprises elements at 410, 420, 430, 440, 450, and 460(representing utility information determined from magnetic field signalcomponents at frequencies 60 Hz, 120 Hz, 180 Hz, 240 Hz, 300 Hz, 360Hz). In this case the frequencies 410, 420, 430, 440, 450, and 460 ofpassive suite 1 include a fundamental 60 Hz power line frequency as wellas various harmonics of the fundamental.

FIG. 5 illustrates an active frequency suite. On display 500 of FIG. 5,active component signal frequency suite 7, shown as element 505,comprises elements 510, 520, 530, 540, 550, and 560 (representingutility information determined from magnetic field signal components at20 Hz, 738 Hz, 8778 Hz, 61938 Hz, 179,898 Hz, 486,938 Hz). Thefrequencies 510, 520, 530, 540, 550, and 560 of active suite 7 areactive frequencies intentionally coupled to the utility line by atransmitter device and/or other transmitting element, such as a magneticfield induction stick. As described previously herein, locate data(e.g., depth, position, phase, current magnitude, direction, etc.) maybe simultaneously determined from each of multiple frequencies within asuite and/or from multiple frequencies across suites for display and/orstorage in the locator and/or on a remote computing system. This datamay be presented in various combinations on the display and/or may bestored in a non-transitory memory, or may be presented discretely and/orstored discretely in a non-transitory memory, and/or may be transmitted,via a wired or wireless communications module (e.g., WiFi, cellulardata, Bluetooth, etc.) in the locator, to a local (e.g., notebookcomputer, tablet, cell phone, etc.) or remote electronic computingdevice or system (e.g., a back-end server system).

For example, data from frequency 410, 420, 430, 440, 450, and 460 ofFIGS. 4 and 510, 520, 530, 540, 550, and 560 of FIG. 5 may correspond toa frequency indicator and depth gauge on their respective displays400/500 as shown. As such, each of the depth indications, as well aseach of the lines shown on the displays in FIG. 4 and FIG. 5, representsa separate simultaneously determined depth and position estimate of autility based on signals from the corresponding signal frequencycomponents. Further, each frequency 410, 420, 430, 440, 450, and 460 ofFIG. 4 may correspond to a frequency indicator 412, 422, 432, 442, 452,and 462 and depth gauge 414, 424, 434, 444, 454, and 464 as shown.Likewise, each frequency 510, 520, 530, 540, 550, and 560 of FIG. 5 maycorrespond to a frequency indicator 512, 522, 532, 542, 552, and 562 anddepth gauge 514, 524, 534, 544, 554, and 564 as shown.

Displays 400 of FIG. 4 and 500 of FIG. 5 may also include other gaugesand/or indicators. For example, battery gauge 470 of FIG. 4, which maycorrespond to battery gauge 570 of FIG. 5, may be provided to indicateavailable power left in the utility locator's battery. An array ofbattery gauges 472, 474, and 476 of FIGS. 4 and 572, 574, and 576 ofFIG. 5 may further indicate battery power of other communicativelycoupled locate system devices. Additional indicators, such a GlobalNavigation Satellite System (GNSS) connectivity indicator 480 of FIG. 4or 580 of FIG. 5, Bluetooth connectivity indicator 482 of FIG. 4 or 582of FIG. 5, and wireless local area network (WLAN) connectivity indicator484 of FIG. 4 or 584 of FIG. 5, may be provided on the display fromcommunicatively coupled devices to indicate status of suchsensors/systems within or connected to the utility locator. Theinformation, gauges, and indicators of display 400 of FIG. 4 may, insome embodiments, correspond to the same information, gauges, andindicators present in display 500 of FIG. 5.

In other embodiments, data from multiple frequency suites may bedisplayed simultaneously, either from single frequency components ineach suite or from combinations, averages, and the like from each suite.For example, as illustrated in FIG. 6, display 600 may include fourseparate linear elements (lines) 610, 620, 630, and 640 of various linetypes/dashes. Each line 610, 620, 630, and 640 may be representative ofdata determined from component frequency signals in a separate frequencysuite. For example, data generated from component signals in frequencysuite 1, shown as element 612, may correspond to line 610, datagenerated from component signals in frequency suite 2, shown as element622, may correspond to line 620, data generated from component signalsin frequency suite 3, shown as element 632, may correspond to line 630,and data generated from component signals in frequency suite 4, shown aselement 642, may correspond to line 640.

A depth gauge 614, 624, 634, and 644 may be included corresponding todata generated from one of each frequency suite 612, 622, 632, and 642as shown in FIG. 6. Data from each frequency suite may be shownindividually or in combination. For example, combination data may beshown by averaging of signal data within each frequency suit and/orother filtering or combining methods, such as, for example,thresholding, weighted averaging, and/or other methods may be used todetermine a single representative line for each suite, such as lines610, 620, 630, and 640, and/or singular result for each suite for depthmeasurement, such as the depth measurements found with depth gauges 614,624, 634, and 644 and/or other singular representations of data withineach frequency suit.

Display 600 may further include a locator battery gauge 650 as well asconnected device battery gauges 652, 654, and 656 similarly to thoseshown in FIG. 4 and FIG. 5. Display 600 may include other informationfrom communicatively coupled locate system component, such as a GlobalNavigation Satellite System (GNSS) connectivity indicator 660, Bluetoothconnectivity indicator 670, and a wireless local area network (WLAN)connectivity indicator 680.

In other embodiments, all or some frequency suites may be factored todisplay a single linear element (line) per buried utility line asdetermined by the utility locator. For example, as illustrated in FIG.7, display 700 includes a single line 710 representative of a buriedutility. Line 710 may be used to determine location of utility line 712as determined through processing signal components from all or a subsetof frequency suites used in the locator. A depth measurement 714 maylikewise be included to indicate determined depth of utility line 712from the generated data. Display 700 may include other indicators fromcommunicatively coupled locate system devices such as a locator batterygauge 750 and/or an array of connected device battery gauges 752, 754,and 756. Display 700 may further include a Global Navigation SatelliteSystem (GNSS) connectivity indicator 760, Bluetooth connectivityindicator 770, and a wireless local area network (WLAN) connectivityindicator 780.

The devices, systems, and methods of the present invention may determinevarious locate information associated with the utility or utilitiespresent in the locate area. For example, devices, systems, and methodsin accordance with the disclosures herein may be configured to determinethe type of utility present as well as its location and/or depth withinthe ground from a “spectral signature” determined by the utilitylocator. The term “spectral signature” as used herein refers to a set ofmeasurements of magnetic field signals taken at separate signalfrequency components of the frequency suites simultaneously. One exampleof such a spectral signature is a power spectral density measurement ofa passive AC power fundamental and one or more of its harmonics. Othercombinations of signal components, either related (e.g., as harmonics)or unrelated (e.g., with discrete active frequency signal componentscoupled to a utility from a transmitter) may be measured simultaneouslyto determine a spectral signature. The spectral signature may bedetermined by receiving and processing a wideband magnetic field signalacross a bandwidth that extends over two or more frequencies (preferablyall frequencies) of a frequency suite. The wideband signal may beprocessed, such as by using a DFT or other filtering method, tosimultaneously extract discrete frequency signals from the separatefrequency signal components of the frequency suites or groups.

The frequency components measured may include one or more fundamentalfrequencies and one or more of their harmonic frequencies. These may bereceived from passive and/or active sources (while several examples ofpassive source AC power signals are described with respect to theirfundamental frequency and harmonics, active signals may also have one ormore harmonics of a fundamental frequency that can be included in anactive frequency suite). The measurements may be a vector, gradient,and/or combined vector/gradient solution with magnitude, direction, andphase measurements for each frequency component of the respectivefrequency suites. Such a “spectral signature” may also includemeasurements of phase and/or other component signal information.

As illustrated in graph 800 of FIG. 8, graph 900 of FIG. 9, and graph1000 of FIG. 10, signal components as measurements at variousfrequencies may be used to determine various types of information aboutthe utility based on its spectral signature. For example, power lines,water lines, sewer lines, cable TV, and so on may all produce acharacteristic spectral signature. As one example, a pipeline with athin paint coating may cause bleed off of the high harmonic frequencies,similar to the example shown in graph 800 of FIG. 8. As another example,an electric power line may have a series of spikes spaced at oddharmonics frequencies similar to graph 900 of FIG. 9. The spectralsignature for single phase AC power lines may be distinct from threephase power lines due to different harmonic interactions (for example,certain harmonics may cancel each other out in multi-phase powerdistribution lines and/or may be additive depending on the power lineconfiguration, loading, etc.). Various other utility types may bedetermined by spectral surveys of various test environments to identifyparticular spectral signatures of the various underground testenvironment configurations or made be determined by survey measurementin well-document underground environments.

Active signals, such as those illustrated in the example graph 1000 ofFIG. 10 may also generate a specific spectral signature, either due tothe characteristics of the utility or intentionally through constructionof a particular harmonic spectra of the signal coupled from thetransmitter to the utility.

In addition to, or in place of amplitude characteristics, a spectralsignature, such as those shown in FIGS. 8-10, may include phasemeasurements and changes in relative phase (between the harmonics atdifferent positions along the utility). The relative signal amplitudeand direction in the measurement as the utility locator is moved aboutthe locate area by a user may also change due to the environment at thelocate site.

For example, measured phase characteristic within the spectral signaturemay be used to identify a vertical, horizontal, and/or twisting patternof a three phase AC electrical power line as a utility locator is movedabout the locate area. The measured data may also provide additionalutility information such as, but not limited to, the type of utilitydetected.

Both graph 800 of FIG. 8 and graph 900 of FIG. 9 illustrate a 60 Hzfundamental AC power frequency and the first six harmonics thereof. Invarious embodiments, the devices, systems, and methods herein mayreceive and process signals at multiple fundamental frequencies andmultiple harmonic frequencies thereof as measurements of absolute and/orrelative phase and/or other signal information from either active orpassive signals or a combination of both active and passive signals.

As noted above, utility locators in accordance with the presentdisclosure and systems and methods thereof may use the spectralsignature to determine buried utility information using variousprocessing and analysis techniques. For example, step 220 of FIG. 2, inwhich utility information may be determined, may be implemented invarious ways.

In one method embodiment 1100 of such a step, as illustrated in FIG. 11,step 1110 may include acquiring a spectral signature from two or moresignals at different frequencies. In step 1120, pattern recognitionand/or other matching algorithms and/or methods may be applied to thespectral signature to correlate or otherwise match the received spectralsignature with a reference spectral signature associated with aparticular utility and/or environmental configuration. For example,certain types of utility lines may have higher energy on certainharmonic frequencies and lower energy on other frequencies. The receivedspectral signature may be compared to reference spectral signatures todetermine a degree of match thereto, and when a match within apredefined tolerance is met the received spectral signature may bedetermined to be the particular reference signature utility type. Inaddition to magnitude spectral signatures, patterns may be determinedand compared to references based on direction and/or magnitude ofvectors, vertical gradients, and/or other gradient patterns at eachfrequency. These patterns within the spectral signature may bedetermined, upon sufficient match, to be indicative of a type of utilityor utilities present as well as other utility and/or environmentalinformation. For example, cluster analysis (see, e.g.,https://www-users.cs.umn.edu/˜kumar/dmbook/ch8.pdf,https://en.wikipedia.org/wiki/Cluster_analysis which are incorporated byreference herein) or other signal processing techniques may be used todetermine the presence of multiple utility lines clustered together asdetermined through the spectral signature. In addition, as a utilitylocator is moved about a locate area, the amplitude and/or vector and/orgradient of each different frequency component may change based onlocation and particular active and/or passive signal(s) impressed uponthe utility or utilities. The distance from the signal source(s),conductivity of ground material, and various other factors may alsochange the measured spectral signature at each geographic locationwithin the locate operation. Once a locate area is mapped, thedetermined spectral information may be stored as a reference and usedfor comparison in subsequent locate operations in the same area or otherareas with new spectral signatures.

Pattern recognition and/or other matching algorithms and/or methods ofstep 1120 may use artificial intelligence, machine learning, and/orother techniques that are known or developed in the art to determinesuch change/variation and/or other previously unknown patterns inspectral signature and may be used to make determinations about utilityinformation based on information stored within a locate database ofhistoric and/or other spectral signature data.

Such a database may include one or more centralized databases which maybe stored in the cloud and may be cloud storage accessible by otherutility locator devices and/or other computing devices used for locateoperations or back end locate data analysis. In step 1130, utilityinformation may be determined by matching patterns in the receivedspectral signature to database information contained within the utilitylocator or remotely stored and accessed. Such a database may berewriteable and dynamically adjusted based on acquired signal data.Processing may occur in real time and/or be post processed either withinthe utility locator and/or on another external computing system.

FIG. 12 illustrates a method embodiment 1200 for processing spectralsignatures. Step 1210 may include acquiring a spectral signature fromtwo or more signal components at different frequencies. In step 1220,even and odd harmonic frequency components within the spectral signaturemay be separated and/or may be processed and analyzed separately. Instep 1230, ratios of odd and/or even harmonics may be used as a metricto determine utility type and/or other utility information based oncomparisons to reference ratio data.

For example, as a utility locator is moved about the locate area, theamplitude and/or vector and/or gradient of each separate frequencysignal component may change based on the location of the measurement(due, for example, to changes in the underground environment around theutility, such as interaction with other conductors in the area, distancebelow ground surface, ground conductivity, and the like).

Although changes at each frequency may occur in some positions, if thereceived signal at those frequencies is largely from the same utilityline and/or other conductor, ratios of various frequencies to each othermay remain approximately the same as the utility locator is moved abouteven as their amplitudes change (e.g., such as when the generalunderground environment is homogeneous throughout the locate area). Forexample, as a user walks about the locate area equipped with a utilitylocator the amplitude of the 120 Hz and 240 Hz harmonics may increase ordecrease proportionately to each other (e.g., when other utilities areabsent from the area so that they do not create interactions, or whenthe utility is a straight, not interrupted conductor without branching).The proportionate change in amplitude may be used to determine that themeasured signal is from the same utility within the ground and is justbeing located at different positions in the locate area (as opposed toit being a different utility that has the measured signal componentscoupled to it).

FIG. 13 illustrates a method embodiment 1300 for using spectralsignatures to identify utilities. Step 1310 may include acquiring aspectral signature from two or measured signal components at differentfrequencies. In step 1320, predetermined groupings of frequencies withinthe spectral signature may be processed and analyzed separately fromother frequencies. For example, certain utility types may havecharacteristically high and/or low energy at certain harmonicfrequencies. This may be predetermined by testing utility configurationsin test sites or based on data collected at well-known undergroundenvironments. In step 1330, utility information may be determined fromthe signature of the frequency groupings based on comparison toreference data. For example, a spectral signature where the majority ofthe energy is distributed onto even harmonic frequencies may indicate agas line with cathodic protection, whereas a spectral signature wherethe majority of the energy falls onto odd harmonics may indicate anelectric line. Such a method may also include determination of agrouping of frequencies that may be used to identify the utility basedon particular characteristics of known utility types and/orconfigurations at those frequencies.

FIG. 14 illustrates a method embodiment 1400 for using signals atmultiple frequencies to identify utilities. It step 1410, signals at oneor more frequencies may be measured with a utility locator. In step1420, the utility locator may be moved to another position in the locatearea. In step 1430, a signal or signals are measured at the newlocation. Such measurements may include vector, gradient, and/orcombined vector/gradient measurements that may further includemeasurements of absolute and/or relative phase at each frequency withinthe spectral signature. Such measurements may, in some embodiments, bein a polar coordinate system which may include polar angle measurements.In step 1440, signal measurements taken at different locations may becompared. In step 1450, correlations in changes within measurements setsto within a predetermined threshold may be identified.

As a utility locator is moved about the locate area, certainmeasurements at various frequencies may change in a correlated fashion.For example, the polar angle measurement of a signal at one frequencymay change at relatively the same rate and/or direction to that of asignal at an adjacent frequency within the same frequency suite. Thesetwo frequencies may share the same signal generating source coupled tothe same conductor within the ground.

As another example, correlations between frequencies may be based on therate at which change occurs within signal measurements as the utilitylocator is moved about the locate area. For example, adjacentfrequencies within a frequency suite that change in a correlated fashionindicative of a nearby buried utility may change at a faster rate thanthe rate of change within measurements of frequency of background powerline harmonics. Phase measurements and/or vector and/or gradient and/orother signal measurement criteria may be used to identify suchcorrelations.

In step 1460 windowing of a set or sets of measurements identified ashaving correlating changes to within threshold tolerances may be done.In step 1470, each windowed set may be used to base determinations ofutility information on. Outlier frequencies where no correlation isfound in the measurement may, in some embodiments, be considered erroror inaccurate measurements and discarded. For example, a window set ofcorrelated measurements indicative of a buried utility may be used todetermine depth of the utility, while outlier frequency measurementsoutside the windowed set may be omitted when determining the utilityline depth. In yet other embodiments, such outlier frequencies may beindicative of other locate information and be analyzed separately. Insome embodiments, multiple windowed sets may be used, which may furtherindicate the presence of multiple signal sources within the locateenvironment.

FIG. 15 illustrates a method embodiment 1500 to refine measurements ofthe utility locator movements about a locate area. Step 1510 may includecorrelating measurement(s) at one or more frequencies at differentlocations using, for example, method embodiment 1400 of FIG. 14. In step1520, a utility locator equipped with motion tracking sensors or othermotion tracking devices (e.g., GPS, inertial sensors, etc.) may be movedwithin the locate area.

The associated distance and direction of movement data as determined bythe motion tracking sensors may be stored in a non-transitory memory ofthe locator. In step 1530, a prediction of signal measurements at thenew location may be made based on correlating measurement set(s) fromstep 1510. In step 1540, a signal may be measured at the new location.In step 1550, difference between predicted signal measurements from step1530 and actual measurements from step 1540 may be determined. In step1560, adjustments to the movement data determined at step 1520 may bemade based on differences determined in step 1550.

FIG. 16 illustrates a method embodiment 1600 for adjusting bandwidthfilters and/or averaging filter output signals based on rate of movementof a utility locator and/or other criteria during a locate operation. Instep 1610, the utility locator may measure the signal(s) and collectcorrelating sensor data simultaneously. Measurement of signal(s) mayinclude passive and/or active frequency suite signals at variousfundamental and/or harmonic frequencies. Sensor data may include, but isnot limited to, sensor measurements from optical and/or mechanicalground tracking sensors/devices, global navigation satellite systems(GNSS) such as Global Positioning Systems (GPS), inertial navigationsystems (INS) and/or other motion or position tracking sensors, devices,and/or systems included on a utility locator. Details of examplesensors, devices, and systems which may be used in various embodimentsand methods thereof in conjunction with the disclosures associated withFIG. 16 are shown in the various incorporated patents and patentapplications.

In step 1620, a decision may be made as to whether anadjustment/averaging criteria has been met based on the signalmeasurements and/or sensor data collected in step 1610. In someembodiments, the adjustment/averaging criteria may be dependent upon achange in location of the utility locator. For example, the distance ofmovement of the utility locator over a time period based onmeasurements/data of GNSS, INS, other motion/position tracking systemsand sensors, and/or a change or lack of change in measured magneticfield signals at one or more component frequencies may define theadjustment/averaging criteria. In other embodiments, theadjustment/averaging criteria may be based on other sensor data and/orsignal measurements other than those associated with the movement of theutility locator.

If the adjustment/averaging criteria is not met in decision step 1620,the method 1600 may return to step 1610. If the adjustment/averagingcriteria is met in decision step 1620, in step 1630 adjustments to thebandwidth of filters and/or averaging of filter output signals based onmeasurements of input signals and/or other sensor data may be made. Insome method embodiments, the rate by which the utility locator is movedmay determine if, and to what extent, adjustments to the bandwidth offilters and/or averaging of outputs signals are made. For example, whenthe utility locator is slowed or stopped, a narrowing of filterbandwidth and/or a rolling average of the output signals from thefilters may be used to improve signal quality. In some embodiments,meeting of the adjustment/averaging criteria may initiate bothadjustments to the bandwidth of filters as well as an averaging of theoutput signal(s) from the filters. In other embodiments, meeting of theadjustment/averaging criteria may only initiate adjustments to thebandwidth of filters or averaging of the output signals from thefilters. Following the adjustments/averaging of step 1630, the method1600 may return to step 1610.

FIG. 17 illustrates a method embodiment 1700 for implementing a spectralscan of a locate area. In step 1710, a utility locator is moved aboutthe locate area while measuring signals and positional data. In step1720, signal measurements collected in step 1710 may be correlated topositional information collected simultaneously by the utility locator.Such positional information may be determined through optical groundtracking sensors/devices, global navigation satellite systems (GNSS)such as Global Positioning Systems (GPS), inertial navigation systems(INS) and/or sensors, and/or other such position/motion trackingdevices/systems as are known or developed in the art. In step 1730, a“target of opportunity” may be determined. This may be done by, forexample, using methods disclosed herein such as those illustrated inFIGS. 11-16.

As used herein, the term “targets of opportunity” refer to particularlyidentified sources of electromagnetic signal energy and/or noise and/orother electromagnetic/signal anomalies affecting the measurement ofsignal within the locate area. For example, the best available powerline harmonic frequency or frequencies at a location (e.g., 2^(nd) or3^(rd) harmonic, or other harmonics), an induction traffic signal loop,switching power line noise sources, and/or other sources ofelectromagnetic energy may be selected or determined as targets ofopportunity.

In step 1740, determined targets of opportunity from step 1730 may becorrelated with geographical and/or mapping data. The geographic ormapping data may be predetermined and loaded map data, image data,geographic vector data, etc. In step 1750, data associated with mappedtargets of opportunity may be stored in a non-transitory memory of thelocator and/or remotely. Storage mechanisms of mapped targets ofopportunity may include a centralized database which may further becloud storage further accessible by other utility locator devices and/orother computing devices. Such a spectral scan of the locate area and ofpotential targets of opportunity may be performed initially as apre-locate operation and/or as a background process within the utilitylocator during a locate operation.

In various devices, systems, and/or method embodiments one or more ofthe methods 1100 of FIG. 11, 1200 of FIG. 12, 1300 of FIG. 13, 1400 ofFIG. 14, 1500 of FIG. 15, 1600 of FIG. 16, and/or 1700 of FIG. 17 may beused. For example, all aforementioned methods may be combined and/orused concurrently and/or separately to determine utility informationincluding, but not limited to, location, depth, and type of utility.

FIG. 18 illustrates an example use of targets of opportunity. Oncedetermined, targets of opportunity from a spectral scan may be storedwhen collected, and then loaded to a locator for display and use insubsequent locate operations. For example, display 1800 of FIG. 18includes a single line 1810 representative of a buried utility as shownon a utility locator UID display. Line 1810 may correspond to a depthgauge 1816 representative of the determined depth of the detectedutility line. Display 1800 may further include one or more targets ofopportunity presented on the display, such as, for example, overheadpower lines 1820 (shown symbolically based on the previously determineddata) and an induction traffic signal loop 1830 (shown symbolically as acoil).

Displayed targets of opportunity may be presented on the locator fromdata from a prior spectral scan collected, for example, by using amethod such as method 1700 of FIG. 17 in the locate area during aprevious survey or locate operation. During a locate operation wheretarget of opportunity data is present from a prior spectral scan,collected signal measurements may further be refined based on signalmeasurements from the spectral scan. Additional spectral scans may becollected during the subsequent locate operation, and these may bestored in the locator and/or on cloud storage and/or other centralizeddatabase(s) on other computing or locating system devices as eitherlocate data, additional targets of opportunity, or both.

Display 1800 may include additional indicators such as a locator batterygauge 1850. In addition, an array of connected device battery gauges1852, 1854, and 1856 may be rendered on display 1800. Display 1800 mayinclude other information from communicatively coupled devices such as,for example, a Global Navigation Satellite System (GNSS) connectivityindicator 1860, a Bluetooth connectivity indicator 1870, a wirelesslocal area network (WLAN) connectivity indicator 1880, as well as otherindicators (not shown).

FIG. 19 illustrates details 1900 of an example locate operation andassociated collected data. The data may include a number of spectralscan paths 1910, 1920, 1930, 1940, 1950, and 1960 in which spectralscans have been made along the illustrated path lines. A series oftargets of opportunity may be determined along each spectral scan path1910, 1920, 1930, 1940, and 1950. For example, spectral scan path 1910may have targets of opportunity 1912, 1914, and 1916. Spectral scan path1920 may have targets of opportunity 1922, 1924, and 1926. Spectral scanpath 1930 may have targets of opportunity 1932, 1934, and 1936. Spectralscan path 1940 may have targets of opportunity 1942, 1944, and 1946.Spectral scan path 1950 may find a cluster of targets of opportunity1952 and a parallel spectral scan path 1960 that reveals no targets ofopportunity.

Comparison of spectral scans at different targets of opportunity may beused to make a refined determination of location, depth, and/or type ofutility/utilities and/or other conductors in the locate area. Suchcomparisons may be or may include principal component analysis (PCA,see, e.g., https://en.wikipedia.org/wiki/Principal_component_analysis aswell ashttps://www.cs.princeton.edu/picasso/mats/PCA-Tutorial-Intuition_jp.pdfwhich are incorporated by reference herein), independent componentanalysis (ICA, see, e.g.,https://en.wikipedia.org/wiki/Independent_component_analysis andhttps://sccn.ucsd.edu/˜arno/indexica.html which are incorporated byreference herein), and/or other component analysis or correlationmethods.

For example, correlation of spectral scans at targets of opportunity1912, 1922, 1932, and 1942 may be used to determine a location of autility line 1972. The correlation of spectral scan at targets ofopportunity 1914, 1924, 1934, and 1944 may be used to determine alocation of a utility line 1974. The correlation of spectral scans attargets of opportunity 1916, 1926, 1936, and 1946 may be used todetermine the location of a utility line 1976. The utility lines 1972,1974, and 1976 may each be determined from spectral scans along multiplespectral scan paths (e.g., spectral scan paths 1910, 1920, 1930, and1940).

In some embodiments, utility line location and other data may bedetermined from one or more spectral scans along a single spectral scanpath. For example, the cluster of target of opportunity 1952 alongspectral scan path 1950 may be determined to show location and otherdata regarding utility line 1954 that may, in part, run in the samedirection as along spectral scan path 1950. The spectral signature fromutility line 1954 may fall off such that it may be spatially sharp andnot be detected at a nearby parallel spectral scan path 1960.

In some embodiments, the sharpness or rate by which the measured signalswithin a target of opportunity falls off in space within a spectral scanmay indicate information regarding a potential utility or other asset.For example, turning to FIG. 20, details 2000 of a locate operationinclude a number of spectral scan paths 2010, 2020, 2030, and 2040 inwhich spectral scans have been performed along the illustrated pathlines. A target of opportunity may be determined along each spectralscan path 2010, 2020, and 2030. For example, spectral scan path 2010 mayhave a cluster of targets of opportunity 2012, spectral scan path 2020may have a cluster of targets of opportunity 2022, and spectral scanpath 2030 may have a target of opportunity 2032.

Through PCA and/or other component analysis or correlation methods thecluster of targets of opportunity 2012 along spectral scan path 2010 andcluster of targets of opportunity 2022 along spectral scan path 2020 maycorrelate to a like buried asset. For example, the target of opportunityclusters 2012 and 2022 may be from a dipole field source such as atraffic loop. The spectral signatures of the target of opportunity 2032along spectral scan path 2030 may correlate to a field source forexample, from a buried conductive pipe running along spectral scan path2030. The target of opportunity 2032 may be spatially sharp withmeasured signals falling off faster in space than targets of opportunityfrom 1/R³ far field dipole sources such as the target of opportunityclusters 2012 and 2022. Information regarding each buried asset may bedetermined by the sharpness of measured signals within each target ofopportunity.

As further illustrated in FIG. 21A, a spectral scan along path 2100 maybe used to identify a target of opportunity 2100. The distinct edges ofthe target of opportunity 2110 may be used to determine a traffic loop2120. In the spectral scan illustrated within FIG. 21B along path 2150,the gradual transition of the target of opportunity 2160 may be used todetermine a buried utility 2170.

In some embodiments, the apparatus, circuit, modules, and/or systems inthis disclosure may include means for implementing features or providingfunctions as described herein. In one aspect, the aforementioned meansmay be a module comprising a processing element including a processor orprocessors, associated memory and/or other electronics in whichembodiments of the invention reside, such as to implement signalprocessing, switching, transmission, or other functions to processand/or condition transmitter outputs, locator inputs, and/or provideother electronic functions described herein. These may be, for example,modules or apparatus residing in buried utility transmitters, locators,coupling apparatus, base stations, and/or other related equipment ordevices.

In one or more exemplary embodiments, the electronic functions, methods,and processes described herein and associated with utility locators andassociated devices may be implemented in hardware, software, firmware,or any combination thereof in one or more processing elements. Ifimplemented in software, the functions may be stored on or encoded asone or more instructions or code on a computer-readable medium.Computer-readable media includes non-transitory computer storage media.Storage media may be any available media that can be accessed by acomputer. By way of example, and not limitation, such computer-readablemedia can comprise RAM, ROM, EEPROM, CD-ROM or other optical diskstorage, magnetic disk storage or other magnetic storage devices, or anyother medium that can be used to carry or store desired program code inthe form of instructions and/or data structures and that can be accessedby a computer processor. Disk and disc, as used herein, includes compactdisc (CD), laser disc, optical disc, digital versatile disc (DVD),floppy disk and blu-ray disc where disks usually reproduce datamagnetically, while discs reproduce data optically with lasers.Combinations of the above are included within the scope ofcomputer-readable media.

As used herein, computer program products comprising computer-readablemedia including all forms of computer-readable medium except, to theextent that such media is deemed to be non-statutory, transitorypropagating signals.

It is understood that the specific order or hierarchy of steps or stagesin the processes and methods disclosed herein are examples of exemplaryapproaches. Based upon design preferences, it is understood that thespecific order or hierarchy of steps in the processes may be rearrangedwhile remaining within the scope of the present disclosure unless notedotherwise.

Those of skill in the art would understand that data, information, andsignals, such as current signals, magnetic field signals, video and/oraudio signals or data, control signals, or other signals or data may berepresented using any of a variety of different technologies andtechniques as are known or developed in the art. For example, data,instructions, commands, information, signals, bits, symbols, and chipsthat may be referenced throughout the above description may berepresented by voltages, currents, electromagnetic waves, magneticfields or particles, optical fields or particles, or any combinationthereof.

Artisans may implement the described functionality in varying ways foreach particular application, but such implementation decisions shouldnot be interpreted as causing a departure from the spirit or scope ofthe present disclosure.

The various illustrative functions and circuits described in connectionwith the embodiments disclosed herein may be implemented or performed inone or more processing elements with a general purpose processor, adigital signal processor (DSP), an application specific integratedcircuit (ASIC), a field programmable gate array (FPGA) or otherprogrammable logic device, discrete gate or transistor logic, discretehardware components, memory devices, and/or any combination thereofdesigned to perform the functions described herein. A general purposeprocessor may be a microprocessor, but in the alternative, the processormay be any conventional processor, controller, microcontroller, or statemachine. A processor may also be implemented as a combination ofcomputing devices, e.g., a combination of a DSP and a microprocessor, aplurality of microprocessors, one or more microprocessors in conjunctionwith a DSP core, ASICs, FPGAs, or other programmable devices incombination with the above, or any other such configuration ofprogrammable devices as are known or developed in the art.

The steps or stages of a method, process or algorithm described inconnection with the embodiments disclosed herein may be embodieddirectly in hardware, in a software module executed by a processor, orin a combination of the two. A software module may reside in RAM memory,flash memory, ROM memory, EPROM memory, EEPROM memory, registers, harddisk, a removable disk, a CD-ROM, or any other form of storage mediumknown in the art. An exemplary storage medium is coupled to theprocessor such the processor can read information from, and writeinformation to, the storage medium. In the alternative, the storagemedium may be integral to the processor. The processor and the storagemedium may reside in an ASIC. The ASIC may reside in a user terminal. Inthe alternative, the processor and the storage medium may reside asdiscrete components in a user terminal.

The presently claimed invention is not intended to be limited to theaspects shown and described previously herein, but should be accordedthe full scope consistent with the disclosure herein and itsequivalents, wherein reference to an element in the singular is notintended to mean “one and only one” unless specifically so stated, butrather “one or more.” Unless specifically stated otherwise, the term“some” refers to one or more. A phrase referring to “at least one of” alist of items refers to any combination of those items, including singlemembers. As an example, “at least one of: a, b, or c” is intended tocover: a; b; c; a and b; a and c; b and c; and a, b and c.

The previous description of the disclosed aspects is provided to enableany person skilled in the art to make or use embodiments of theinvention. Various modifications to these aspects will be readilyapparent to those skilled in the art, and the generic principles definedherein may be applied to other aspects without departing from the spiritor scope of the invention. Thus, the presently claimed invention is notintended to be limited to the aspects shown herein, but is to beaccorded the widest scope consistent with the appended claims and theirequivalents.

We claim:
 1. A buried utility locator, comprising: an antenna array forreceiving magnetic field signals from a buried utility in two or moreorthogonal directions, the antenna array having a bandwidth including aplurality of predefined signal frequencies in a predefined firstfrequency suite; a receiver operatively coupled to the antenna array forgenerating a receiver output signal including amplitude and/or phaseinformation of first two or more signal components in two or moresimultaneously received signals of the first frequency suite; aprocessing element operatively coupled to the receiver for receiving thereceiver output signal and generating a first set of data associatedwith the two or more signal components of the first frequency suite; anon-transitory memory for storing the first set of data; and a displayto render a visual output corresponding to the determined first set ofdata.
 2. The locator of claim 1, wherein the first frequency suitecomprises a passive frequency suite including signal components at twoor more passive frequencies, and the first set of data is based on thetwo or more passive frequency signal components.
 3. The locator of claim1, wherein the first frequency suite comprises an active frequency suiteincluding signal components at two or more active frequencies, and thefirst set of data is based on the two or more active frequency signalcomponents.
 4. The locator of claim 1, wherein the first frequency suitecomprises a signal component at a passive frequency and a signalcomponent at an active frequency, and the first set of data is based onthe passive frequency signal component and the active frequency signalcomponent.
 5. The locator of claim 1, wherein the antenna array has abandwidth including a second plurality of frequencies in a secondfrequency suite, the receiver generates the output signal to includesecond two or more signal components in two or more frequencies in thesecond frequency suite, the processing element generates a second set ofdata associated with the second two or more signal components, and thesecond set of data is stored in the non-transitory memory.
 6. Thelocator of claim 5, wherein the first frequency suite comprises anactive frequency suite including signal components at two or more activefrequencies, and the first set of data is based on the two or moreactive frequency signal components.
 7. The locator of claim 6, whereinthe first frequency suite comprises an active frequency suite includingsignal components at two or more active frequencies, and the first setof data is based on the two or more active frequency signal components.8. The locator of claim 6, wherein the second frequency suite comprisesa passive frequency suite including signal components at two or morepassive frequencies, and the second set of data is based on the two ormore passive frequency signal components.
 9. The locator of claim 5,wherein the first frequency suite comprises a signal component at apassive frequency and a signal component at an active frequency, and thefirst set of data is based on the passive frequency signal component andthe active frequency signal component.
 10. The locator of claim 9,wherein the second frequency suite comprises a signal component at apassive frequency and a signal component at an active frequency, and thesecond set of data is based on the passive frequency signal componentand the active frequency signal component.
 11. The locator of claim 1,wherein information associated with the buried utility based on the twoor more signal components of the first frequency suite is rendered onthe display.
 12. The locator of claim 1, further comprising a module forgenerating positional information of the locator, wherein the positionalinformation of the locator is associated with the two or more signalcomponents and stored in the non-transitory memory.
 13. The locator ofclaim 12, wherein the module for generating positional information is aGPS receiver module and the positional information is latitude andlongitude information.
 14. The locator of claim 1, wherein the generateddata associated with the two or more signal components of the firstfrequency suite comprises separate depth information of the buriedutility determined based on ones of the two or more signal components.15. The locator of claim 1, wherein the generated data associated withthe two or more signal components of the first frequency suite comprisesseparate positional information of the buried utility relative to thelocator determined based on ones of the two or more signal components.16. The locator of claim 5, wherein the generated data associated withthe first two or more signal components and the second two or moresignal components comprises separate depth information of the buriedutility determined based on ones of the first two or more signalcomponents and ones of the second two or more signal components.
 17. Thelocator of claim 5, wherein the generated data associated with the firsttwo or more signal components and the second two or more signalcomponents comprises separate position information of the buried utilitydetermined based on ones of the first two or more signal components andones of the second two or more signal components.
 18. The locator ofclaim 1, wherein the generating data associated with the two or moresignals of the plurality of frequencies includes generating the datausing a discrete Fourier transform (DFT) on the receiver output signalto extract amplitude and/or phase information from ones of the signalsof the plurality of frequencies.
 19. The locator of claim 1, wherein theplurality of frequencies of the first frequency suite comprise passivesignals based on a fundamental and/or harmonics of a power linefrequency.
 20. The locator of claim 19, wherein the power line frequencyis 50 Hz or 60 Hz.
 21. The locator of claim 1, wherein the plurality offrequencies of the first frequency suite comprise active signals basedon a fundamental and/or harmonics of a utility transmitter output signaldirectly or inductively coupled to the buried utility.
 22. The locatorof claim 1, wherein the first set of data associated with the two ormore signal components is associated with a first utility of the one ormore buried utilities, and the first set of data is presented on thedisplay as a single linear element corresponding to the first utility.23. The locator of claim 22, wherein data from the first set of data isaveraged to generate the single linear element on the display.
 24. Thelocator of claim 23, wherein the display includes a rendered map orimage of the locate area and the two or more linear elements aresuperimposed on the map.
 25. The locator of claim 1, wherein the firstset of data associated with the two or more signal components isassociated with a first utility of the one or more buried utilities, andthe first set of data is presented on the display as two or moreseparate linear elements corresponding to a representation of theutility based on simultaneously received and processed datacorresponding to the two or more signal components.
 26. The locator ofclaim 25, wherein the display includes a rendered map or image of thelocate area and the two or more linear elements are superimposed on themap.
 27. The locator of claim 5, wherein the first set of dataassociated with the two or more signal components is associated with afirst utility of the one or more buried utilities, the second set ofdata associated with the second two or more signal components isassociated with a second utility of the one or more buried utilities,the first set of data is presented on the display as one or more linearelements corresponding to the first utility, and the second set of datais presented on the display as one or more linear elements correspondingto the second utility.
 28. The locator of claim 1, wherein a spectralsignature is determined from the first set of data, and a first utilitytype is determined based on comparison of the determined spectralsignature and a reference spectral signature.
 29. The locator of claim28, wherein the first utility type is determined to be a water pipeline.30. The locator of claim 28, wherein the first utility type isdetermined to be an AC power line.
 31. A method for locating buriedutilities, comprising: receiving, at an antenna array for receivingmagnetic field signals from a buried utility in two or more orthogonaldirections, a plurality of magnetic field signals emitted from a commonsource at predefined signal frequencies in a predefined first frequencysuite; generating, in a receiver coupled to an output of the antennaarray, a receiver output signal including amplitude and/or phaseinformation of first two or more signal components in two or moresimultaneously received signals of the first frequency suite;generating, in a processing element coupled to the receiver, a first setof data associated with the two or more signal components of the firstfrequency suite; storing, a non-transitory memory of the locator, thefirst set of data; and rendering, on a display of the locator, a visualoutput corresponding to the determined first set of data including atleast two different representations of a position and/or a depth of theutilities with each of the different representation based on a separatesignal component of the first frequency suite.
 32. The method of claim31, wherein the antenna array has a bandwidth including a secondplurality of frequencies in a second frequency suite, the receivergenerates the output signal to include second two or more signalcomponents in two or more frequencies in the second frequency suite, theprocessing element generates a second set of data associated with thesecond two or more signal components, and the second set of data isstored in the non-transitory memory.